Connection drop when transfer large file

[psyap]

We are using a IBM T40 (with 802.11b build-in). We are able to surf web and ping successfully. Once we transfer large file, the connection just drop and the debug log from the AP1200 shows:

Dec 18 10:39:57.095 H: %DOT11-4-MAXRETRIES: Packet to client xxxx.xxxx.xxxx reached max retries, removing the client

Dec 18 10:39:57.095 H: %DOT11-6-DISASSOC: Interface Dot11Radio0, Deauthenticating Station xxxx.xxxx.xxxx Reason: Previous authentication no longer valid

However, when we try using Cisco 350 PCMCIA cards and Orinoco, there is no problem with the large file transfer.

We have upgraded the driver to the latest version.

Any help. Thks

[pradeepde]

This type of error is usually because of RF interference. When the AP sends a packet to the client, the client must ACK this packet back to the AP, if the AP receives no ACK from the client, it will resend this packet. It will continue this process for 16 times (default config) before assuming the client is off the network now (person moved out of range or powered off their computer) and will remove the client from its association table. I would verify coverage via a site survey, looking at not only signal strength, but also signal quality